400 hp

im runing arap 6e bin moded do you think the timeing is to much for my 355 with vette 113 heads.. or ok. my motor is the same as a vette. i have the lt4 hot cam. and 10.5.1 cc

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86 z28 th350 trans built jegs 2400-2800 stall
355 HSR lt4 hot cam 1.6 rockers vette 113 heads ported. bbk 52mm tb
dougs long tube headers. custom y pipe flowmaster ex hooker aero chamber muffler 10 bolt 3.42 gears pbr rear brakes hp pads.hotchkis frame conectors.

dan0617

I ran those heads (on a stock bottom end) reworked and bigger valves, HSR intake, CC 503 cam (224/230 duration), and ran 36 degrees overall, without detonation. My knock sensor system was disabled. My static CR was 10.2:1. I would think that my cam was bleeding off a little more of the compression than yours, and so were my piston rings. (had alot of blow-by). My guess is that you would want to run nearer to 34 degrees overall, all in by around 3600 rpms. I had my timing drop down a little right around the torque peak.

Probably around 24 to 26 degrees at idle, ramping up very quickly to get up nearer 38 to 40 by the cruise range rpms. Start bringing the timing down (especially below 3200 rpms and alot below 2400 rpms) pretty quickly when the load gets up to and over 128. With the converter locked and giving alot of gas in overdrive and around 1600 to 2000 rpms mine was always very detonation prone and didn't want much timing in that area. (heavy load, low rpms)

This was always with 92 octane gas. If running 87 octane be more conservative on the timing and keep it on the rich side, and consider going colder on the spark plugs.

This is all just to give you an idea, all engines are different and you might find yours is way off from what mine was.

I got away with running closed loop, and I would think you will be able to. I did have a touch of cam surge in the cruise rpms at very light throttle but I was only running 3.07 gears. I think lower gears would have cleared it up. Was going to try open loop with more fueling and timing in the cruise rpms but ended up going with a 383 over the winter. As a side note, I now run a 230/236 cam and had more surge than with the 350 but I did go to open loop and enrich the fueling and timing in cruise rpm area and now have my surge down to a very minimum.

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'89 MAF car, tune by me with help from this forum. 383 with Eagle forged internals, AFR 195 streets, 230/236 cam, HSR intake with custom plenum, Hooker 2151's, Crane CD ignition, 2800 stall, built 700R4, Nittos, Zex 225 shot. Best so far 10.66 @ 131.08.

400 hp

thanks i will give that a try my motor runs better with the arap timeing table. ive 0 out all the extra timeing. like pe and runing 6* for base.

__________________
86 z28 th350 trans built jegs 2400-2800 stall
355 HSR lt4 hot cam 1.6 rockers vette 113 heads ported. bbk 52mm tb
dougs long tube headers. custom y pipe flowmaster ex hooker aero chamber muffler 10 bolt 3.42 gears pbr rear brakes hp pads.hotchkis frame conectors.

dan0617

Whatever you have your distributor set at with the EST unhooked (your initial timing), you need to have your base timing in the tune set at the same. So, if you have your initial timing at the distributor set at 6, set the base timing in the tune at 6.

I also zero out the PE spark advance when I tune. Then when I'm sneaking up on detonation, trying to figure out how much timing I can run at WOT, I'll add 2 degrees to the PE spark advance and run it. If no detonation, I'll add 2 more degrees (and usually a touch of fuel in the PE fueling table) and try it again. Once I find where I get detonation I'll back off 2 to 3 degrees, add it to the main SA table, and zero out the PE spark advance again.

I found I like the ARAP timing table to start with but the farther from stock I get the more timing I have to pull from it, in different areas depending on the changes I make to my setup.